A controversial Nazi-themed production of Richard Wagner's Tannhäuser has been cancelled after it caused some audience members to seek medical help and prompted others to walk out in anger.The Rheinoper in Düsseldorf said it was in a state of shock after being deluged with complaints by members of the public who called the opera tasteless and unnecessarily provocative.The production, which opened last Saturday and was expected to be one of the highlights of the celebrations for the bicentenary of Wagner's birth later this month, has a Nazi storyline, and includes scenes of people dying in gas chambers, being shot and raped, and of members of a family having their heads shaved before their execution....